Coal-drill



(No Model.) K

M. HARDSOCG.

Patented Apr. 9, 1895.

GOAL DRILLl NITED STATES IPATENT OEEICE.

MARTIN IIARDSOOG, OF OTTUMWA, IOIVA.

COAL-DRILL.

SPECIFICATION forming part of Letters Patent No. 537,287, dated April 9, 1 895.

Application filed January 23, 1894. Serial No. 497,747 (No model.)

To ctll'whom t may concern:

Be it known that I, MARTIN HARDsocG, a

citizen of the United States, residing at Ot-y tumwa, Iowa, have invented certain new and useful Improvements in Coal-Drills, of which the following is a specification.

The object of my invention is to provide a simple, economical and efficient coal drill; and my invention consists in the features, combinations and details hereinafter described and claimed.

In the drawings, Figure l is a front elevation of myimproved drill and detachable bit; Fig. 2,- a side elevation of a portion,partly in section, taken on line 2 of Fig. 1;' Fig. 3, a transverse section, takenon line 3 of Fig. 1; Fig. 4, a front elevation of the detachable bit;

and Fig. 5 a side elevation ot'Fig. 4..

In constructing my improvement, I makea body portion, A, of the twist drill type, formed by twisting a flat drill into the desired shape and pitch, and provide it with a shank, B, bifurcated for reasons hereinafter set forth. I provide a recess at the frontend of the body portion by offsetting the same, as at C, and combining with it a removable anged clip, D, provided with side flanges, 61,61, which form the desired recess between them. De-

` tachably secured in this recess is a bit, E,

having a bifurcated shank portion e, which enters the recess and is securely clamped therein by means of the bolt, G, which is screw-threaded in the clip and passes through ythe slot of the bifurcated shank, in such man- The odset C of the drill is tapered toward the shank and the flanges d of the cap D correspondingly tapered to engage the odset. This construction prevents the parts f rom being disengaged during the withdrawal of the drill from a hole.

The advantages consequent to the use of my improved drill are that a body portion of any desired length can be used in connection with the detachable bit, or several body portions can be secured together to make a long working drill. Again, several bits may be used in connection with one body portion, so thatduring the sharpening or forging processes it would not be necessary for the operator to remain idle.

I am aware that the idea of removable bits and extension drills is not new, and do not desire to be understood as claiming this idea broadly. Nor do I wis'h to be unduly limited, any more than is pointed out in the claim, as I contemplate slight variations in form, con# struction and arrangement, as circumstances may suggest or render expedient, without de= parting from the spirit of the invention;

I claim-e In coal drills, the combination of a body portion having a shank at one end and an offset C at the front end tapering toward the shank, a removable cap O provided with tapered flanges d adapted to fit the tapered offset and form a recess between it and the offset, a bit portion provided withwa bifurcated shank detachably secured in such recess, and a bolt to rigidly hold such parts together, substantially as described.

THOMAS A. BANNIG, THOMAS F. SHERIDAN. 

